The invention relates to an arrangement for controlling access of persons, in particular an arrangement with access lanes adapted for the individual passage of these persons.
Such arrangements that control access of persons are known, for example, for ski lifts and aerial tramways, but also for other places providing public access. Arrangements of this type are also used in buildings where access to the building is restricted to a specific group of persons. In most cases, access is provided in the form of access lanes which allow persons to pass one at a time. A barrier device is located inside the access lanes, wherein the barrier device is released after access authorization has been verified. Access authorization may be based on an electronic ticket that does not make physical contact, or on a magnetic card or a card with a bar code.
Typically, the barrier devices are implemented as turnstiles. Conventional turnstiles typically include three rods which are offset from each other by 120 degrees and secured to a shaft of the turnstile. Adjacent rods may enclose an acute angle with each other. When a person passes through the turnstile, the shaft is rotated by 120 degrees, so that the rod which originally extended into the passage lane, now lets the person pass, whereas the rod which before pointed towards the person passing through is now in the barrier position. The type of barrier where the rotation axis of the shaft is oriented at an acute angle to the passage plane, is generally referred-to as a turnstile. Turnstiles can adequately control the individual passage of persons, but are frequently viewed as inconvenient.
Another type of barrier arrangement includes a shaft which is oriented perpendicular to the passage plane, with the rods rotating in a horizontal plane. This arrangement provides improved comfort over the arrangement described above, but requires a fair amount of space equal to at least the width of a passing lane.
To make it easier for persons to pass through the turnstile, the shaft in both arrangements may be rotated by a motor. A turnstile having the first arrangement has been proposed, where the shaft has only a single rod which executes a 360 degree rotation for each passage. Since the drive torque applied by the motor must be small enough so as not to cause bodily injuries, the arrangement with a single rod may not be able to reliably provide access for one person at a time.
It is therefore an object of the invention to improve an access control arrangement of the type described above by providing more comfort for the user and a reliable access for one person at a time.
The invention provides an arrangement for controlling access of persons with access lanes adapted for the passage of these persons one at a time, wherein with each access lane there is associated a turnstile and a reader for access authorization. The turnstile includes a motorized shaft for rotation, wherein the axis of rotation is inclined at an acute angle with respect to the access plane. The shaft includes two rods which are offset relative to the axis of rotation by 180 degrees, for blocking the access lane. A respective one of these rods can be rotated from a blocking position where the rod extends into the passage lane, into a position where the rod points towards the ground in order to let a person pass through.
Arrangements of the type described above typically require mechanical and electronic components for each access lane. These components are arranged in separate devices located on the side of the access lanes. Separate additional devices are also required for the blocking means, which are most frequently implemented as turnstiles. Conventional arrangements disadvantageously require considerable space, and their appearance may make the user feel claustrophobic.
The invention overcomes these disadvantages by providing a single control device which is located between two adjacent access lanes. The identification and/or blocking means are arranged on the respective left and right side of the control device, as viewed in the passage direction. The control device may include two housing shells which form a floor support and may also receive the identification and/or blocking means. The housing shells may be symmetric and made of cast aluminum. Further advantages of the invention will be discussed below with reference to a specific embodiment.
Access is frequently authorized based on an electronic ticket which can operate without making physical contact. Such tickets may include a transponder with a transmitter/receiver which, after activation by an electromagnetic field in a reader, retransmits data. Known readers typically have an antenna formed as an air coil and arranged on the side of the access lane. The coil may also be routed inside a tubular frame. Alternatively, a pan with a plastic lid and made of cast aluminum may be provided. The air coil may then be supported by the plastic lid.
The antenna construction of these arrangements, however, is complex and may limit the range at which the tickets can be read. Moreover, the arrangement may make the user feel claustrophobic.
The invention overcomes these disadvantages by constructing each antennaxe2x80x94when viewed in the direction of accessxe2x80x94of two spaced apart vertical pipes, with an electrically insulating plate extending between the pipes. A conducting loop forming a transmitter/receiver circuit is arranged behind the plate, as viewed from the access direction. This feature provides a sufficient reception range and at the same time may make the user feel less claustrophobic.
The tickets can be read reliably from one side by extending between the vertical pipes of the antenna a second plate which is remote from the first plate and at least partially electrically conducting.
It is also possible to implement an access control system without employing a turnstile or barrier, for example, for the purpose of statistically sampling the number of persons passing through or for optically indicating when access is authorized. With this type of access terminal, however, adjacent antennas from several access lanes may interfere with each other.
It is therefore also an object of the invention to mitigate these problems by providing an access control system that is less complex.
According to the invention, an access terminal has at least two antennas for reading RFID transponders without making physical contact with the transponders. The antennas are connected to common transmission/receiving electronics, wherein at any given time only one of the antennas is actively connected to the common transmission/receiving electronics via a multiplexer, while the inactive antennas are shorted, damped or detuned.
This approach reduces the complexity of the electronics and has the advantage that different antennas or access lanes no longer interfere with each other.
According to another advantageously feature of the invention, the common transmitter/receiver electronics and the antenna are connected in a manner that a short circuit in an antenna is converted into an open circuit at the respective terminal of the transmitter/receiver electronics. The length of the connecting line is preferably equal to one quarter of the wavelength of the selected carrier frequency of the transponder system.
The programming logic according to the invention for controlling an access terminal with a plurality of antennas is advantageously designed so that at any given time a multiplexer sequentially connects only one antenna to the transmitter/receiver electronics, with the remaining antennas being shorted or detuned. The multiplexer may actively switch the connected antennas rapidly in sequence, whereby the sequence performed by the multiplexer is halted from the time a transponder is recognized in the reception range of an antenna until the reading process is concluded.